Topoisomerase II inhibitors induce cGAS-STING dependent inflammation resulting in cytokine induction and immune checkpoint activation

Abstract

Tumours with genomic instability demonstrate enhanced immunogenicity and potential for response to immune checkpoint blockade (ICB). We previously demonstrated activation of the cGAS-STING pathway following loss of DNA repair, resulting in cytokine induction, lymphocytic infiltration and immune checkpoint activation. Here we explore the role of chemotherapies in inducing this innate immune response, identifying topoisomerase II (topo-II) inhibitors, particularly doxorubicin and epirubicin, as potent inducers of a cGAS-STING dependent interferon response. Mechanistically, topo-II inhibition resulted in significant induction of cytoplasmic DNA and subsequent micronuclei formation, a requirement for efficient cGAS-STING activation and consequent cytokine and immune checkpoint gene induction. Importantly, increased cytokine and immune checkpoint gene expression, as well as increased immune cell infiltration, was also observed in patient derived breast tumour biopsies following topo-II inhibitor-based treatment. Taken together, this study indicates topo-II inhibitors such as doxorubicin, may be best placed to induce immunogenic inflammation, and thereby increase responses to ICB therapies. Running Title: Topoisomerase II inhibitors induce cGAS-STING activation SignificanceThis work demonstrates how topo-II inhibitors induce STING-pathway activation, cytokine induction and immune checkpoint protein upregulation in cancer cells and provides a rationale for combining topo-II inhibitors with ICB therapy in early breast cancer.3

Copper Complexes as Anticancer Agents Targeting Topoisomerases I and II

“…Top1-DNA covalent cleavage complex enables cGAS-mediated cytoplasmic chromatin recognition and immune checkpoint response [ 221 ] ( Figure 5 B). Top2 inhibitors teniposide and doxorubicin potentiate the therapeutic immune checkpoint blockade therapies based on anti-PD-1 (programmed cell death 1) in multiple types of mouse tumor models [ 222 , 223 ]. Besides, ROS produced by Top inhibitors alter the molecular pattern recognized as immunogenic structures and enhance apoptosis [ 224 ] ( Figure 5 B).…”

An in silico analysis identifies drugs potentially modulating the cytokine storm triggered by SARS-CoV-2 infection

“…In fact, Topoisomerase-I activity has been found to mediate the expression of inflammatory genes 36 . In contrast, Topoisomerase-II inhibition triggers the expression of inflammatory cytokines through activation of cGAS-STING innate immune sensing of cytoplasmic DNA 37 .…”

The DNA damage induced immune response: Implications for cancer therapy

“…Interestingly, we and others have shown that in HR defective tumour cells, e.g. BRCA1/2 deficient cells, fragments of dsDNA, thought to be by-products of replication fork instability in a HR defective background, are exported to the cytoplasm, where they act as substrates for cGAS, leading to STING dependent innate immune activation [51][52][53]. Additionally, it has been shown that large chromosomal fragments induced either directly by DNA damage, or missegregated during mitosis as a result of persistent/unrepaired DNA damage, are encapsulated within micronuclei when the nuclear envelope reassembles after mitosis.…”

“…Additionally, it has been shown that large chromosomal fragments induced either directly by DNA damage, or missegregated during mitosis as a result of persistent/unrepaired DNA damage, are encapsulated within micronuclei when the nuclear envelope reassembles after mitosis. cGAS accumulates within these micronuclei, leading to potent cGAS and subsequent STING activation upon micronuclei rupture, which can occur spontaneously or during a second round of mitosis [51][52][53]. In this context, intrinsic genomic instability leads to activation of the cGAS/STING pathway (Fig.…”